Sample Procedure: Project 2 Reaction A
Vanillin (2.0 mmol) and sodium iodide (2.2 mmol) were combined in a round bottom flask. Ethanol (3 mL) was added, and the mixture was stirred to dissolve the solids. A solution of calcium hypochlorite (1.5 mmol) in distilled water (9 mL) was added dropwise to the reaction mixture over ~10 minutes. The mixture was stirred for an additional 5 minutes, then a solution of 0.1 M ascorbic acid (1.8 mL) was added to quench the reaction. A drop of reaction solution was added to starch-iodide paper. If the paper turned dark (indicating the presence of iodine), additional 1.8 mL aliquots of ascorbic acid solution were added until the reaction mixture tested negative by starch-iodide paper. The mixture was then poured into 9 mL of ice-cold water and acidified with 3 M HCl (3 mL). The solids were collected by vacuum filtration and recrystallized from a mixture of 75:25 ethanol:water.
Reminders & Hints
1. Don’t forget to fully prepare your Lab Notebook according to the guidelines before entering the lab.
2. The Background section of your Lab Notebook should include a table of reagent quantities for the reaction. An example can be found here.
3. Remember that you are NOT performing this procedure as written. You must scale the quantities used in the reaction so that your theoretical yield is 2.0 grams. The Reaction Scaling Workshop walks you through this process and allows you to verify your plan.
4. Timesaver: The Ca(OCl)2 takes some time to dissolve. Prepare the solution as the first step of your procedure. Mix the components in an Erlenmeyer flask, add a stir bar, and let the mixture stir while you are setting up the reaction.
5. You must complete the Project 2A Prelab Quiz before entering the lab to perform this procedure.
6. You must decide how to characterize your product in order to determine the success of your reaction.
7. In the Lab Techniques section, a variety of resources are available for you to review the technique of recrystallization prior to performing this procedure. It is strongly recommended that you watch the Recrystallization Review video before lab.